Manufacture of steel



F. B. WALDRON MANUFACTURE OF STEEL Filed July 19, 1949 l m N March 4, 192

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Patented Mar. 4, 1952 UNITED STATES PATENT OFFICE MANUFACTURE OF STEEL Frederic Barnes Waldron, Eccleston Park, Prescot, England Application July 1'9, 1949, Serial No.v 105,516 In Great Britain April 1949 lllitherto it has been proposed to take a separate batch o1 a separate furnace full of metal and place it in communication with a vacuum chamber from which the gases are drawn oil" and after this treatment the metal is run oif intermittently in to moulds.

These vacuum chambers for use with continuously nov-ving' metal have hitherto always taken the form of an inverted U channel and none proposed to use an open chamber of sufcient height to allow the molten metal to rise an appreciable height inside it.

Some or" these proposals have included means for heating the vacuum chamber or the metal therein but the devices for doing this have been confined to electrical resistance heating or heating of the molten metal by channel type electric induction which requires an internal solid core contained in a refractory insulating casing.

According to this invention the steel is made by a continuous process such as is described in my British Patent No. 543,245 accepted 1942, and while it is flowing continuously in the molten state it is caused to pass through an enclosed gas tight chamber which is maintained at a pressure appreciably below that of the outside atmosphere.

A convenient method of carrying out the invention is shown in the accompanying drawing in which Fig. l is a sectional elevation showing one way in which the plant may be arranged.

Fig. 2 is a sectional elevation showing an alternative arrangement of the plant.

Referring to Fig. 1 steel in an advanced state ci reiining hows continuously from a persistent source along channel It into furnace II which is shown with electrodes 28 for an electric refining process on the metal. The metal flows thence continuously along channel I2 into hearth I3.

Chamber I5 stands at a higher level than i'urnace il. It is made gas tight and the gases in it re drawn oif by a vacuum pump 24 driven by electric motor 25. The pipe 2! connects the hot chamber t5 to the pump and coils of it 23 pass through the cooler 22 and reduce the temperature of the gases until they can be safely taken by the pump. Waterenters the cooler by pipe 26 and leaves by pipe 2l.

The vacuum maintained in chamber I5 may be such to Keep the level of the metal in it at 4 to 5 feet higher than the level of the metal in hearth I3 A pipe Id lined with flreclay dips into the metal in hearth I3 and connects with the bottom of chamber I5 so that the metal will iiow continuously from one to the other by virtue of the vacuum. Another similar pipe I'I on the opposite side and at the bottom of chamber I5 conducts the metal continuously down to hearth I8 in which the metal level is kept lower than that in hearth I3 by an amount chosen to ensure the required rate of flow through chamber I5.

Chamber I5 may be heated by coreless induction 3i) from an alternating electric current and applied to a pocket IB arranged below the main hearth of the chamber. The resultant agitation will assist in liberating the gases and a metallurgical process may also be included if desired.

The molten metal in hearth I8 having been degasied as described above may flow on continuously through chamber i9 in which it may flow quietly or be cooled or be heated by electrodes 29 for further renement. It ows thence by channel 20 into moulds or it may flow continuously to a plant for forming it into commercial shapes. Such plant may be for tube making as described in my United States Patent No. 2,359,453.

Fig. 2 shows another convenient arrangement of the plant embodying the same principles as the plant shown in Fig. 1. Molten metal from a persistent source iiows through furnace II along channel I2 into hearth I3 which connects with the bottom of chamber Si. This chamber is of suiiicient height to allow the metal in it to rise 4 or 5 feet higher than the metal in hearth I3 and the space above this metal is maintained at a vacuum which will cause the metal to rise this amount. The pipe 2l connects through a cooler to a vacuum pump similar to that shown in Fig. 1.

An outlet at the bottom of chamber 3| connects to hearth I8 in which the metal is kept lower than that in hearth is by an amount chosen to ensure the required rate of flow through chamber 3l.

The molten metal through channel 32.

Fig. 1 and Fig. 2 show only one upper degasifying chamber but the number of such chambers is not limited and a chamber of type i5 may be followed by a chamber of type 3! or they may be i'iows on continuously connected in the reverse direction and the later one or more may be used for cooling the molten metal after it has been degasii'led. The degasii'lcation chambers may be preceded or followed by any number of chambers of furnaces and in any of them the metal may be heated or cooled or may be subjected to any suitable metallurgical process.

The types of chambers and other plant are convenient ones as shown but any others may be used and any other type of heating and cooling may be adopted.

Having described my invention I declare that what I claim ls:

l. A method of extracting gases that are occluded in molten steel which comprises continuously flowing such molten steel into the bottom of an enlarged chamber which ls maintained under Vacuum, continuously and unrestrictedly flowing the molten steel through said chamber while it rises therein to a substantial height due to the vacuum in said chamber whereby the occluded gases are separated from the steel and are withdrawn from said chamber by a gas eX- traction appliance and withdrawing the degasied steel from a point at the bottom of said chamber into a chamber at atmosphere pressure.

2. A method of extracting gases that are occluded in molten steel which comprises continuously flowing such molten steel into the bottom of an enlarged chamber which is maintained un- 4 der Vacuum and in which the steel is heated and agitated from below by coreless electric induction, continuously and unrestrictedly flowing the molten steel through said chamber while it rises therein to a substantial height due to the vacuum in said chamber whereby the occluded gases are separated from the steel and are withdrawn from said chamber by a gas extraction appliance and withdrawing the degasified steel from a point at the bottom of said chamber into a chamber at atmospheric pressure. v

VFREDERIC BARNES WALDRON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re.11,737 Wainwright Apr. 25, 1899 310,012 Aitken Dec. 30, 1884 414,397 Goetz Nov. 5, 1889 669,466 McRae et al. Mar. 5, 1901 1,077,925 Baraduc-Miller Nov. 5, 1913 2,054,921 Betterton Sept. 22, 1936 2,054,922 Betterton Sept. 22, 1936 2,140,607 Thompson Dec. 20, '1938 2,253,421 De Mare Aug. 19, 1941 FOREIGN PATENTS Number Country Date 543,245 lGreat Britain Feb. 16, 1942 

1. A METHOD OF EXTRACTING GASES THAT ARE OCCLUDED IN MOLTEN STEEL WHICH COMPRISES CONTINUOUSLY FLOWING SUCH MOLTEN STEEL INTO THE BOTTOM OF AN ENLARGED CHAMBER WHICH IS MAINTAINED UNDER VACUUM, CONTINUOUSLY AND UNRESTRICTEDLY FLOWING THE MOLTEN STEEL THROUGH SAID CHAMBER WHILE IT RISES THEREIN TO A SUBSTANTIAL HEIGHT DUE TO THE VACUUM IN SAID CHAMBER WHEREBY THE OCCLUDED GASES ARE SEPARATED FROM THE STEEL AND ARE WITHDRAWN FROM SAID CHAMBER BY A GAS EXTRACTION APPLIANCE AND WITH DRAWING THE DEGASIFIED STEEL FROM A POINT AT THE BOTTOM OF SAID CHAMBER INTO A CHAMBER AT ATMOSPHERE 